In today's refining environment, the economics of operating a refinery unit (e.g. a reformer) depends on the proper selection of feedstocks and the real time optimization of refinery unit output profile in response to changing market conditions. Both the selection of feedstock and the optimization of output profile depend on timely analysis of the feedstock composition and product output. Such monitoring may involve inputting composition data into mathematical models to monitor the performance of the process units.
Refineries periodically monitor reformer units by performing detailed analyses of feeds and products. The most accurate manner to perform such analysis is to use a complex gas chromatographic analyzer using multi-columns (i.e. multi-dimensional) approach. Such analysis has also been called PIONA analysis. The analyzers performing PIONA analysis can be more costly, require higher maintenance than simpler one-dimensional gas chromatographic analysis based on a single boiling point type of capillary column and detection by flame ionization detection. The one dimensional analysis is called detailed hydrocarbon analysis (DHA). Therefore, there are advantages using the simplified DHA in a laboratory (less cost, easier to maintain and operate, provide detailed data for lower carbon number hydrocarbon species, etc.).
Comparison of the test reports, generated by PIONA and DHA separately but on the same sample, reveal variances in the amount of specific compounds contained in the feedstock. For example, there may be up to an approximately >5% difference in naphthene content, a >3% difference in paraffin content and a >2% difference in aromatics content, between the PIONA and DHA analyses. These variances translate into potential multi-million dollar losses of margin improvement, per year, per reformer when DHA analysis is used to monitor reformer unit operation compared to the use of PIONA analysis. There is a need to improve the accuracy of reformer units using less costly DHA analysis.